v0.7.0: char-width + status bar fix — TDD (RED→GREEN)

char-width: contract 5, 4 tests (6 assertions), 100% pass
  ASCII=1, CJK/Hangul/Kana/halfwidth=2, combining marks=0, tab=8
  Pure Lisp, ~25 lines, no deps. Used by word-wrap for unicode.

status bar: contract 6, timestamp right-aligned at (- w 12)
  Fixes overlap where focus map and timestamp both drew at :y 2 :x 1

lisp/channel-tui-state.lisp

@@ -112,8 +112,6 @@ See *tui-theme-presets* for named presets (dark, light, solarized, gruvbox).")
               :input-buffer nil :input-history nil :input-hpos 0
               :messages (make-array 16 :adjustable t :fill-pointer 0)
               :scroll-offset 0 :busy nil :cursor-pos 0
-              :pending-ctrl-x nil :scroll-at-bottom t
-              :scroll-notify nil)
               :dirty (list nil nil nil))))
 
 (defun now ()
@@ -145,9 +143,6 @@ See *tui-theme-presets* for named presets (dark, light, solarized, gruvbox).")
 
 (defun add-msg (role content &key gate-trace)
   (vector-push-extend (list :role role :content content :time (now) :gate-trace gate-trace) (st :messages))
-  ;; v0.7.0: if scrolled up, set notification flag
-  (unless (st :scroll-at-bottom)
-    (setf (st :scroll-notify) t))
   (setf (st :dirty) (list t t nil)))
 
 (defun queue-event (ev)